[Rd] eval(SEXP fn,SEXP rho) in C++ code

[Patricia Bautista]

Hi r-devel, 

I am working on a R extension. I am writing the
function in C++, and in my function it is required a R
function object from the user. This R function object
will be evaluated thousand of times in my C++ code. I
generated the shared library and I loaded it on R. I
did several experiments in order to compare the speed
of my compiled code vs the speed of the equivalent
interpreted code. I was surprise!, the better was  the
interpreted code!. Then, I ask myself: What is the
benefit of compiled code??.  I think my problem is in
using the function "eval(SEXP f, SEXP rho)" because it
takes time!. Am I right?. Then, can someone tell me
what  the benefit of using compiled code is?, or can
someone give me a reference to look into?.

Thanks in advanced,
Patricia B.